On Tue, 20 Jul 2004 10:21:32 -0400,
(Nicolai Carpathia) tried desperately to walk and chew gum at the same
time (post on-topic while trying to discredit me) by writing in
:

On 19 Jul 2004 05:01:36 GMT, (ROCH USMC) wrote in
: *Hi
*Here is what I just got, Cobra 29 LTD Classic that was bumped up a bit,
a new Palomar Elite 300 amp (ebay) , Diesel (?) noise canceling mic and
a Wilsom 5000 mag mount ant.
I cant get the SWR down below 2.5. I ran a new 18' cable and a ground
wire to the frame of the truck but ever time i key up the ANT light
lights up on the radio.
My questions a
1. How can I get the SWR down?

Just three words: Grounding, grounding, and

grounding. You need to ground the radio AND

the amp AND the antenna.


The antenna is already grounded. A Wilson mag mount needs no additional
ground.


A magnet isn't a any type of electrical connection at all. Some have
been duped into thinking there's a capacitive coupling between the
magnet and body through the paint, but fail to realize that the magnet
itself prevents any capacitive coupling. That's why most mag-mounts
come with 18' of coax yet frequently show high SWR. And unless the
antenna is a dummy load, you can move the cable around and watch the
SWR needle wander.

Fact: Mag-mount antennas have ****-poor ground connections.


By "grounding" I

mean an "RF ground". At 27MHz, this means

mounting the radio and amp directly to the

chassis and/or using grounding straps that are
no more than a few inches long. Only after

your system is properly grounded can you

address any other issues.


Nonsense. One can mount the radio in a slide mount and to make it
temporary or it can be mounted in a permanent manner.


Nobody said it couldn't. A slide mount is fine if the receiver half is
mounted to the chassis (or with a very short grounding strap).


It can be mounted
to the dash and a myriad of other places.


Strip the plastic and vinyl from the dash, and behold... the chassis!
The chassis also exists in a "myriad of other places".


The radio does not need
directly mounted to the chassis in order to provide proper grounding. In
fact, this is less practical and not the manner of which the majority of
cb installs are complete.


It's very practical. It just takes a little extra effort.


And those other issues can be many.

Almost as many as there are ways in which to mount the radio other than
mounted directly to
the chassis.


For example, your 'bumped' Cobra may have

been 'bumped' by a moron; your Palomar may
have a detuned input or output, a bad power

transistor, or even worse it might be

self-oscillating; you might be using cheap coax
(never use foam!); you might have a bad

antenna; etc. But regardless of the problem,

it's always easier to troubleshoot if the system

is properly grounded.


*2. Is this a good combo?

Not really.


Sure it is. Palomar amps work quite well.


When fed with the correct input levels. A radio that has been 'bumped'
(which I assume to mean it has been tweaked for more power) may easily
exceed the maximum input levels for the amp. Even 4 legal watts will
overdrive most of the smaller amps.


The makers of these cheap linears

(that usually aren't very linear at all) don't tell

you that the power rating is for -peak- power.





LOL,,umm,,that's how amps are rated.
You used the term linear, he called it an amp.


Unless his Cobra is capable of FM, your point is moot.


One that is familiar enough to add new coax to a Wilson is more than
likely already aware of this.


IOW, a 300-watt amp will do 300 watts PEP,

which translates to a maximum of 75 watts

RMS (AM carrier power). Push it any harder

and you will get a bigger carrier, but you start

clipping well below 100% modulation,

splattering your signal across the spectrum.


Watts are watts, regardless of how they are measured. Refer to them as
RMS, PEP, or BIRD, as you have in the past...watts are watts. With many
radios, the blue faced palomar 250 are will sing 100 watts all day long
without bleeding and they are very cheap.


A common misconception, hence the frequent and continuing occurances
of RFI, and the increasing popularity of LP filters.


You also appear to be incorrect pertaining to modulation, as there are
many instances pertaining to cb, when one wishes to achieve loudest
optimum modulation, a power mic is required. Many times, this can cause
the bleed over to begin. Remove the power mic in many applications, and
the bleed can often be removed. I don't expect you to follow, Frank,
you're still smarting after having your head handed to you after making
the stupid comment that fiberglass antennas can have nothing to do with
bleed issues.


CB radios have modulation limiters which prevent modulation from
exceeding 100% (usually set for 90-97%). A power mic may clip and
distort the audio, and if that happens just turn down the mic. But if
the limiter has been disabled (as some monkey-techs like to do, one of
their stupid "CB tricks"), the result is that the RF will start
clipping and/or become unsymmetrical, both of which cause harmonics
and 'splatter'.

And overdriving an amp is ALSO a cause of harmonics, as I described
before. Cheap CB amps like the Palomar are rated in watts PEP, even
though they don't specify them as such. The way to tell is to look at
the spec sheet of the power devices (transistors) and find out how
those are rated, which is usually for PEP. That is the case for the
Palomar in question. The difference is that AM is measured in RMS.
With an AM radio that does 4 watts RMS (which is also the carrier
power), it outputs 16 watts PEP at 100% modulation. So if your AM
radio is driving your 300-watt amp to 300 watts carrier -without-
modulation, the result is some big-time distortion because the amp is
incapable of meeting the 1200 watts PEP requirement for an AM signal
at 100% modulation.


You should have had your Cobra 'dumped'

instead of 'bumped'.


That's a personal opinion coming from one who doesn't know any better
and bases his technical advice on nothing but personal emotion. Slight
peaking and tuning is perfectly acceptable when done by a competent
technician. In fact, Many cb radios can use a tune-up alignment after
being shipped.


Most experienced ampheads have their radios 'detuned' for -lower-
output power to prevent overdriving the amp. That's a fact, not my
personal opinion.


As for a mag-mount, personally, I wouldn't

waste my money.


Again, you don't know any better. Many of us have talked around the
world on mag mounts, barefoot, on a regular basis. Mag-mounts are great
solutions for temporary mounts, rental cars, quick disconnects, etc.
Money spent on a Wilson is not wasted.


It is to me because I don't need temporary mounts. If I want to remove
the antenna I just unscrew it. And I don't rent vehicles, I buy them.


But you have,

Again, a perjorative personal opinion of yours. Lockheed Martin proved
the efficiency of the Wilson in independent tests. You should check
their test data and you may grasp why they are so popular and have
legions of loyal customers,,,they make a tight product that delivers
what they claim.


Phen-fen had the support of independent tests and legions of loyal
customers....
Firestone had the support of independent tests and legions of loyal
customers....
Asbestos had the support of independent tests and legions of loyal
customers....
DDT had the support of independent tests and legions of loyal
customers....etc, etc, etc.


so you should know that 18' of

coax isn't a reliable substitute for the terrible

grounding characteristics of mag-mount

antennas. If you want real power you need a

real antenna, not a glorified refrigerator

magnet.

"Real" is a relevant term. The Wilson will have no problem with the
amplifier he is using.
_

*3. on my amp it has a ON/OFF , HIGH, MED, LOW and a PRE-AMP on and off.
* What is with the PRE- AMP.

The pre-amp is used to amplify the received

signal. They are mostly worthless because the
usually much better than the S/N ratio of the

pre-amps. IOW, they will just make the noise

louder. However, they work great for older and
low-end transceivers, and simple homebrew

receivers.


The pre-amps are worthless by no means. They work absolute wonders when
the needle is flat with no noise for those extreme fringe stations. I've
used a cheap pre-amp on a regular basis to talk to the east coast of Fl
late at night,,,BAREFOOT.


That's because you run a Tentec.

Oh, and up North we have come up with a really cool invention that has
been adopted by the vast majority of civilized society. It's called
the "shoe".


*Ok I know I will take a beating from some of you and that is part of
the game but any help or any suggestions would be great.

Here's your beating: If you want to play

'hammie', get a license.


Running an amp isn't "playing hammie" to all, just to those anal
retentive status starved individuals.


If you can't afford a license (about the price of

a happy-meal), or if the test is too difficult

(even when you are allowed to memorize the

questions and answers before the test), then

at least get yourself a book on the subject and
learn what you are doing.


Seeing as he can solder and change out a coax on a Wilson,


He never claimed to have done anything of the sort. Your communication
deficit is acting up again, Twist.


it appears he
is learing what he is doing quite fine. If one wanted a hammie license,
I am certain one would find that information if that is what they were
seeking.
With all the bull**** you have given this dude, he may run like hell
from anything hammie related, merely because someone like yourself is
advocating it, and he wouldn't be blamed for doing so. It's just the
manner in which you come across to all those you can't understand.


You're just jealous because I haven't given you a good beating for a
while. Now go back to trollville and behave yourself until you are
summoned for your next beating.




=============

http://tinyurl.com/ytcah
http://tinyurl.com/2yor7
http://tinyurl.com/2sapq
(Twisty cast the first stone)

=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."

"...but as usual, your best simpl isn;t good enough."

"Athis is how proper communication wroks..."

---- Twistedhed ----

=============


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